The purpose of this project is to determine which second messenger pathways are involved in receptor regulation of rat adrenal medulla and spleen, and ultimately brain enkephalin levels. The enkephalin promotor contains a NFKB site, which may be important for responses to steroids. Glial (and possibly neuronal) enkephalin levels are known to be increased by elevating cAMP, and we have demonstrated a glucocorticoid potentiation of this stimulation. This potentiation involves an overcoming of neuronal inhibition of glial enkephalin production by glucocorticoids, the mechanism is as yet unknown. Spleen enkephalin levels appear sensitive to NFKB regulation; we have also observed a surprising sex difference in enkephalin levels in the spleen. We are presently comparing adrenal, spleen and cultured brain cell transcription factor levels and their responses to agents known to elevate enkephalin levels, to determine whether the enkephalin gene is regulated similarly or differently in each of these tissues.